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https://issues.apache.org/jira/browse/CASSANDRA-14118?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16404752#comment-16404752
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Joshua McKenzie commented on CASSANDRA-14118:
---------------------------------------------

bq. And yes, not using the C* commit log would probably preclude supporting cdc.
Correct. It's current implementation is constrained by the 1:1 requirement (if 
it persists to disk, it's available for consumption, if it doesn't, it's not) + 
desire to keep heap pressure from the feature to a minimum (i.e. don't cache 
AllTheThings, then mark them in memory as persisted on CL flush, then fragment 
that memory out if offheap or pressure GC if on on reclaim, etc etc etc).

i.e. it's using the CL as the mechanism of persistence + "communication" with 
an external process reading the files, so you don't write it to the CL, you 
don't get "CDC".

> Refactor write path
> -------------------
>
>                 Key: CASSANDRA-14118
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-14118
>             Project: Cassandra
>          Issue Type: Sub-task
>          Components: Core
>            Reporter: Dikang Gu
>            Assignee: Dikang Gu
>            Priority: Major
>
> As part of the pluggable storage engine effort, we'd like to modularize the 
> write path related code, make it to be independent from existing storage 
> engine implementation details.
> For now, refer to 
> https://docs.google.com/document/d/1suZlvhzgB6NIyBNpM9nxoHxz_Ri7qAm-UEO8v8AIFsc
>  for high level designs.



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